BETHESDA, MD 08 June 2011—A new drug safety communication from FDA warns health care providers not to use the highest approved dosage of simvastatin—80 mg—in new patients.
In addition, patients who currently a take lower daily dose of simvastatin should not have their dosage raised to 80 mg/day, FDA stated. The warning is intended to reduce patients` risk for serious muscle injury associated with simvastatin use.
According to FDA, the 80-mg/day dosage is only appropriate for patients who have taken that amount for at least 12 months and have no symptoms of myopathy.
An FDA analysis of safety data indicated that the risk of myopathy is highest during the first 12 months of simvastatin treatment and decreases substantially after that time. This pattern also holds true for rhabdomyolysis, a potentially deadly form of myopathy, according to FDA.
Single-ingredient simvastatin is sold in generic form and under the brand name Zocor, by Merck. Other simvastatin-containing combination products available in the United States are Vytorin, which contains simvastatin and ezetimibe, and Simcor, which contains simvastatin and niacin. These medications contain 10–80 mg of simvastatin per dose.
FDA estimated that approximately 2.1 million U.S. patients were prescribed a product containing 80 mg of simvastatin during 2010.
New information from today`s announcement is being added to the labeling for simvastatin-containing products. Also to be added are new contraindications stating that the drug must not be used concomitantly with itraconazole, ketoconazole, posaconazole, erythromycin, clarithromycin, telithromycin, HIV protease inhibitors, nefazodone, gemfibrozil, cyclosporine, or danazol.
The updated labeling also recommends reduced dosages of simvastatin when the drug is given concomitantly with amiodarone, verapamil, diltiazem, amlodipine, or ranolazine.
Patients who require a medication that adversely interacts with simvastatin should be switched to another statin, according to FDA.
The agency advised patients who currently take the 80-mg/day dosage of simvastatin not to stop taking the medication without first speaking to their health care provider.
Patients with possible symptoms of muscle wasting, such as muscle pain, tenderness or weakness, dark or red colored urine, or unexplained tiredness, should immediately seek advice from their health care provider, according to FDA.